Time duration == scrape interval returns no results

[WilliamDEdwards]

My scrape_interval is set to 15s. When doing a PromQL query with the same time duration, e.g.:

rate(mysql_global_status_slow_queries{job=~"cluster-mariadb"}[15s])

... the result set is empty. However, when using e.g. 16s, oftentimes, results are returned.

This causes issues for me when using Grafana, because many Grafana dashboards build PromQL queries where time duration == scrape interval. And as no results are returned, visualizations show 'no data'. (The scrape interval that Grafana uses is derived from the data source, and should be the same as Prometheus's.) Specifically, I am experiencing this issue with Grafana Labs' official 'MySQL Exporter Quickstart and Dashboard' dashboard.

Am I (or Grafana Labs) doing something wrong, or is this a known issue?

[WilliamDEdwards]

Found it: https://grafana.com/blog/2020/09/28/new-in-grafana-7.2-__rate_interval-for-prometheus-rate-queries-that-just-work/

Grafana Labs' official 'MySQL Exporter Quickstart and Dashboard' dashboard still uses $__interval rather than $__rate_interval. And I don't see a way to report issues with them.

Sorry for the noise, as this is obviously not related to Prometheus.